Oxidation of delta4-3, 6-dihydroxy steroids to delta4-3-keto-6-hydroxy steroids



' 2,786,855 Patented Mar. 26,- 1957 OXIDATION OF A -3,6-DiHYDRXYSTEROIDS TO A -3-KET0-6-HYDRQXY STEROIDS Franz Sondheimer and "GeorgeRosenkranz, Mexico City, Mexico, assignors to Syntex S. A., Mexico City,Mexico, a corporation of Mexico No Drawing. Application January 27,1954, Serial No. 406,571

Claims priority, application Mexico January 31, 1953 6 Claims. (Cl.260-397.4)

The present invention relates to cyclopentanophenam threne compounds andto a method for the preparation thereof. More particularly, the presentinvention relates to the oxidation of steroid compounds with manganesedioxide.

In our United States patent application Serial No. 364,184, filed June25, 1953, there is disclosed the oxidation of steroidal A -3,6-dihydroxycompounds with manganese dioxide at room temperature to thecorresponding A -3-keto-6-hydroxy compounds and at elevated temperaturesto the corresponding A -3,6-diketones respectively. in theaforementioned application there is also disclosed the oxidation ofsteroidal A -3, hydroxy compounds with manganese dioxide to form thecorresponding A -3- ketones.

In United States application Serial No. 344,246, filed March 23, 1953,there is disclosed the oxidation of steroidal allyl alcohols withmanganese dioxide.

in accordance with the present invention, we have discovered thatmanganese dioxide may be utilized for the oxidation of A -3,6-dihydroxycompounds of the pregnene and androstene series with the production insome instances of novel A -6-hydroxy-3-ketones of the androstene andpregnene series. Certain of the 6-hydroxy compounds have already beendisclosed as of substantial pharmacological interest and others of the6- hydroxy compounds produced in accordance with the present inventionmay be readily converted as for example to known 6-keto compounds. Since6/3-hydroxy compounds are produced by biochemical means (United StatesPatent No. 2,602,769) the production of 6,B-hy droxy compounds bychemical methods becomes important for comparison therewith and for theproduction of the same 6-keto compounds for comparative purposes.

It has further been discovered in accordance with the present inventionthat A -pregnene-3 8,17a-diol--one (flu-hydroxy pregnenolone) may betreated withmanganese dioxide to give the novel A -pregnadien-17a-ol-3,20-dione (the 6-dehydro derivative of the cortical hormonel7-hydroxyprogesterone, easily converted into the cortical hormone byconventional reduction). Similarly, treatment of A pregnene3/3,17a,2l-triol-20-one 21- acetate (21-acetoxy, Her-hydroxypregnenolone) with manganese dioxide produces A -pregnadien-l7u,2l-diol-3,20-dione 21-acetate (21-acetate of the 6-dehydro derivative of thecortical hormone Reichsteins substance S).

It has been also discovered in accordance with the present inventionthat oxidation of an allyl alcohol with manganese dioxide (as disclosedin the aforementioned United States application Serial No. 344,246) maybe utilized to prepare steroidal A -12-keto compounds from thecorresponding A -12-hydroxy compounds and steroidal A -21 aldehydes fromthe corresponding A al-alcohols.

in practicing the invention the steroid to be treated is preferablydissolved in an organic solvent such as chloroform and shaken at roomtemperature with manganese dioxide for a prolonged period for selectiveoxidation of the hydroxy group. For the reactions with manganese dioxidein the hot the steroid is similarly dissolved and refluxed withmanganese dioxide for several hours.

The following specificexamples serve to illustrate but are not intendedto limit the present invention:

Example 1 A solution of 2 g. of the diacetate of A -pregnene-3B,6,8-diol-ZO-one prepared in accordance with Journal of Organic Chemistry 16,192 (1951) in 100 cc. of methanol was treated with 1.5 g. of sodiumhydroxide previously dissolved in 10 cc. of water and the mixture wasrefluxed for one hour, poured into water and extracted with ether. Theether solution was washed to neutral and dried over sodium sulphate.Direct crystallization from ether afforded 55% yield of A-pregnen-3/3,6,8-diol- 20-one having a melting point of 188-192" C., [a](chloroform) 500 mg. of A -pregnene-3fi,6fl-diol-ZO-one dissolved in cc.of chloroform was shaken for 24 hrs. at room temperature with 10 g.- ofmanganese dioxide. The solution was filtered and evaporated to dryness.Crystallization of the residue from acetone-ether yielded 260 mg. of A-pregnen-6B-ol-3,ZO-dione having a melting point of 173-l74 C. (theanalytical sample had 181-183 C.), [a] (chloroform). The compound has anultraviolet absorption maximum at A max. 238 III/L (log a 4.26). Theinfrared spectrum confirms the presence of a free hydroxy group as wellas the A -3-keto and 20- keto groups.

A solution of 500 mg. of 6 8-hydroxyprogesterone in 2 cc. of pyridineand 2.5 cc. of acetic anhydride was heated on the steam bath for 1 hr.and. then poured into water. The product was worked up under theusualconditions and crystallization from ether-hexanegave 100% yield of theacetate of A -pregnen-6B-ol-3,20-dione having a melting point of 141-143'C., [al l-95 (ethanol). The compound has an ultraviolet absorptionmaximum at A max. 236 m (log 6 4.28). The infrared spectrum confirms thepresence of an acetylgroup as well as the ZQ-lteto and A -3-keto groups.a

The following equation illustrates the process of the present example:

e5 d .9 a

700 mg. of A -pregnene-3,B,6 3-diol-20-one was dissolved in 80 cc. ofchloroform and mixed with 8 g. of mangane'se dioxide. Themixturewasrefluxed under stirring for 6 hrs., filtered and evaporated todryness. The .residue was chromatographed in a column with 30 g. of

washed aluminum oxide. The crystalline fractions eluted I I Example IIIA solution of 13 g. of the triacetatc of A pregnene-3,8,65,2l-triol-20-one prepared in accordance with Journal of OrganicChemistry 16, 192 (1951) in 300 cc. of methanol was mixed under anatmosphere of nitrogen with a solution of 13 g. of sodium hydroxide in60 cc. of water after both solutions had been cooled, and the mixturewas kept undernitrogen for 24 hrs. at room temperature. It was thenneutralized with acetic acid, concentrated to a small volume underreduced pressure, poured into water and the precipitate was extractedwith chloroform. Crystallization from chloroform-ether gave 8 g. ofA*-pregnene-3;8,6,B,21-triol-20-one having a melting point of ZOO-203 C.(the analytical sample had a melting point of 203206 C.).

A solution of 970 mg. of'A pregnene-3,9,6,8,2l-triol- 20-one in 2.5 cc.of anhydrous pyridine was cooled to C. and mixed with 1.2 molarequivalents of acetic anhydride previously cooled to 10 C. The flask wasquickly stoppered and then kept for 24 hrs. at a temperature of 10 C.,poured into water and extracted with ether. Chromatography followed byone crystallization from acetone afiorded 490 mg. of the 21-monoacetateof A -pregnene-3p,6fi,21triol-2O-one having a melting point of 190-192C. (the analytical sample had 193-195 C.). The infrared spectrum showsthe presence of the free hydroxy groups and the 21-acetoxy and 20-ketogroups.

10 g. of manganese dioxide was added to a solution of 1 g. of the2l-acetate of A -pregnene-3p,6/3,21-triol-20- one in 100 cc. ofchloroform and the mixture was shaken for 24 hrs. at room temperature,filtered and evaporated to dryness. Crystallization from acetone-etheryielded 600 mg. of the 21-acetate of A -pregnene-6B,2l-diol- 3,20-dionehaving a melting point of 198-200 C. The compound has an ultravioletabsorption maximum at A max. 238 m (log e 4.26). The infrared spectrumconfirms the presence of free hydroxy, 21-acetoxy, 20-keto and A -3-ketogroups.

300 mg. of Gfi-hydroxy-desoxycorticosterone 2l-acetate was acetylatedwith 1 cc. of pyridine and 1.5 cc. of acetic anhydride by the methoddescribed in Example No.1. Crystallization from ether-pentane gave 300mg. of the diacetate of A -preg'nene-6fl,21-diol-3,20-dione having amelting point of 128-130 C., [a] +1O1 (chloroform). The ultravioletspectrum has an absorption band at 236 my (log e 4.18).

. 4 The following equation illustrates the process of the presentexample:

I I) 1 ii] .4) (;l in... 11

I I5 Ii] on Example IV M In the same way as described in Example II, 1g. of the 21-acetate of A pregnene-3fi,6fi,21-triol-2O-one in cc. ofchloroform was treated with 10 g. of man ganese dioxide. Chromatographyof the product and recrystallization from acetone-ether yielded 260 mg.of the acetate of A -pregnen-21-ol-3,6,20-trione (acetate of6-keto-desoxycorticosterone) having a melting point of 137-139" C.,ultraviolet absorption maximum at A max. 248 m (log 1: 4.05). Theinfrared spectrum confirms the presence of an acetyl and ZO-keto group,as well as the presence of a A -3,6-diketone.

The following equation illustrates the process of the present example:

CHzOAG CHzOAc 0 50 l ii] I r 1 HO-- 0= Example V 3 g. of manganesedioxide was added to a suspension of 1 g. ofM-androstene-3g618-diol-17-one (prepared by saponification of diacetate;Petrow et al. Journal Chem. Soc. 2536 (1949)) in 100 cc. of chloroformand the mixture was shaken for 24 *hrs. at room temperature. Thesolution was filtered and evaporated to dryness. Crystallization fromchloroform-ether afforded 600 mg. of A -androsten-6B-ol-3,l7-dionehaving a melting point of 187189 C. (the analytical sample had a meltingpoint of 192194 C.), [a] +1l5 (chloroform). The compound shows anultraviolet absorption maximum at A max. 236 m (log 6 4.27). Theinfrared spectrum indicates the presence of a free hydroxy group and17-ket0 and A -3-keto groups.

300 mg. of 6B-hydroXy-androstene-3,17-dione was acetylated with 1 cc. ofpyridine and 1.5 cc. of acetic anhydride such as described in Example I.The product was crystallized from chloroform to give mg. of the acetateof M-androsten-6fl-ol-3,17-dione having a melting point of -194" C.(analytical sample, melting point 19820l C.), [a] |106 (acetone). Itshows an ultraviolet absorption maximum at A max. 234 m (log 6 avenues4.21). The infrared spectrui'n'confirms the presence of 17-keto and A-3,keto groups.

The following equation illustrates the process of the present example:

o; QU

(into Example VI g. of manganese dioxide was added to a suspension of lg. of A -androstene-3fi,6/3-diol-17-one in 100 cc. of chloroform and themixture was refluxed for 8 hrs. under stirring. The solution wasfiltered and evaporated to dryness and the residue was chromatographedin a column with 50 g. of previously washed aluminum oxide. Thefractions having similar melting points were combined, thus giving 310mg. of A -androstene-3,6,17-trione having a melting point of 220-221 C.,[u] |43 (acetone). The compound shows an ultraviolet absorption maximumat max. 248 m (log e 4.20). The infrared spectrum confirms the presenceof the 17-keto group and has an additional band at 1680 cmrcharacteristic of unsaturated carbonyl groups.

The following equation illustrates the process of the present example:

Example VII A suspension of 2 g. of lithium aluminum hydride inanhydrous ether was slowly added to a solution of 4 g. of the diacetateof A -androstene-3[3,6fi-di'ol-17-one in tetrahydrofurane. Afterdecomposing the excess of reagent by the addition of acetone, water was.added and the precipitate was filtered and washed. Crystallization fromchloroform produced 2.36 g. of A -androstene- 35,65,17/3-tri0l having amelting point of 208-212" C., [a] +13 (dioxane). This compound has noselective absorption in the ultraviolet spectrum and the infraredspectrum indicates the presence of free hydroxy groups.

1 g. of A -androstene-3p,613,17B-triol was dissolved in 100 cc. ofchloroform and oxidized with manganese dioxide such as described in theprevious examples, at room temperature. Crystallization fromchloroform-ether gave 480 mg. of A androstene 65,175 diol 3 one having amelting point of 215-216 C., [111 (chloroform), max. 238 m (log 641.25). The infrared spectrum shows the presence of free hydroxyl and A-3-keto groups.

250 mg. of this 6,3-hydroxytestos'terone was acetylnted by the methoddescribed in previous examples. Chroma tography and crystallization fromether-pentane yielded mg. of the diacetate of A-anclrostene-6B,l7B-diol-3- one having a melting point of 132-l33 C.,[al +26 (chloroform), max. 234 m (log e418). The infrared spectrum showsthe presence of the acetate group as well as the A -.3-ket0 group.Similar esterification produced other conventional esters especiallylower fatty esters, such as the propionate, or aromatic esters such asthe benzoate.

The following equation illustrates the process of the present example: Y

QAo

xample VIII :13 g. of manganese dioxide was added to a suspension of1.37 g. of A*-androstene-3,B,6fl,17/8-triol in cc. of chloroform and themixture was refluxed as described in the previous examples.Chromatography and crystallization from acetone-ether produced 500 mg.of A -androsten-17B-ol-3,6 dione having a melting point of 213- 215 C.,[al 52 (acetone), A max. 250 m (log 6 4.17). The infrared spectrumreveals the presence of a free hydroxy group and shows a band at 1,680cmr characteristic of unsaturated carbonyl groups.

The following equation illustrates the process of the present example:

Example IX '7 x The following equation illustrates the process of thepresent example:

3 g. of 21 acetoxy 17a hydroxy pregnenolone dissolved in 300 cc. ofbenzene was oxidized with 30 g. of manganese dioxide under reflux suchas described in previous examples. Chromatography and crystallizationfrom chloroformether yielded 1 g.'of the 21-acetate of A pregnadiene170:,21 diol 3,20 dione having a melting point of 218-221 C., [ofl +104(chloroform), A max. 284 m (log 6 4.48). The infrared spectrum indicatesthe presence of the 21acetoxy group, a free hydroxy group and the20-keto and unsaturated keto groups.

A solution of l g. of this 21-acetate of A -pregnadiene-17a,21-diol-3,20-dione (G-dehydro derivative of Compound S) in 50 cc. ofacetic acid and 50 cc. of benzene was shaken under an atmosphere ofnitrogen for 20 hrs. at room temperature with 2 g. of granulated zinc(30 mesh) and 0.2 g. of ascorbic acid. The zinc was filtered and thesolution was evaporated to dryness. The residue was collected with'chloroform and the solution was washed with water and again evaporatedto dryness. Crystallization from acetone afiorded 0.8 g. of the 21-acetate of A -pregnene-17a,21-diol-3,20-dione (acetate of ReichsteinsCompound S) having a melting point of 239-441 0., [1 +116 (acetone).

, The following equation illustrates the process of the present example:

- ii iii 9Q glfi EOQL sac Example XI 3.2 g. of the Zl-acetate of A-pregnane-17a,2l-dio1- 3, 20-dione was dissolved in 300 cc. ofchlorobenzene and 20 cc. of the solvent was distilled in order to removetraces of moisture. Then 8 cc. of carbon tetrachloride with 0.8 cc. ofanhydrous pyridine and 1.6 g. of well powdered N-bromosuccinimide wasadded and the mixture was refluxed for 12 minutes with a photofiood lampas source of light and heat. The mixture was cooled, washed with water,dried over sodium sulphate and evaporated to dryness at not too high atemperature under reduced pressure. The residue crystallized uponaddition of ether. Recrystallization from acetone-ether gave the21-acetate of 6 bromo A pregnene 1711,21 diol 3,20 one having a meltingpoint which varied between 168 and 177 C., [041 +56 (chloroform).

1.2 g. of this 6-bromo derivative was refluxed for 30 minutes with 15cc. of distilled collidine, the precipitate of collidine hydrobromidewas filtered and the solution was diluted with ether, washed with dilutehydrochloric acid and water, dried over sodium sulphate and evaporatedto dryness. Recrystallization of the residue from acetoneether affordedthe 21 acetate of A pregnadiene- 170:,21 diol 3,20 dione having'amelting point of 221223, [al +102 (chloroform). This compound has anultraviolet absorption maximum at 284 Hl/L (log "e 4.50). By directcomparison it showed to be identical to the product obtained inaccordance with the method of Example X.

The following equation illustrates the process of the present example:

CHaOAc Example XII 500 mg. of A -22a-allospirostene-318,l2fi-dioldissolved in 50 cc. of chloroform was oxidized with 5 g. of manganesedioxide shaking for 4 hrs. at room temperature such as described inprevious examples. Crystallization from chloroform-acetone yielded 370mg. of A 22a-allospirosten-3p-ol-12-one having a melting point of220-223 C., [ab-27 (chloroform, 7\ max. 240 m (log a 4.20). The infraredspectrum of this compound shows the presence of a free hydroxy group andhas a band at 1670 cm.- characteristic of an unsaturated keto group. e

The following equation illustrates the process of the present example:

OHIOAQ Example XIII 500 mg. of A -pregnadiene-3 8,2l-diol dissolved in50 cc. of chloroform was oxidized with 5 g. of manganese dioxide shakingfor 5 hrs. 'at room temperature such as described in previous examples.Crystallization from acetone afforded 325 mg. of A -pregnadien-3fl-ol-21-al having a melting point of 1781'80 C., 7\ max. 244 m (log 6 4.29).

The following equation illustrates the process of the present example:

CHOH GHO We claim: 1. A process for the production of a A -3-keto-6-hydroxy compound selected from the group consisting of compounds of thepregnen series and compounds of the androstene series which comprisestreating a corresponding A -3,6-dihydroxy compound with manganesedioxide at room temperature.

2. The process of claim 1 wherein the A -3-ket-o-6- hydroxy compound isA -pregnene-6fi-ol-3,20-dione.

3. The process of claim 1 wherein the A -3-keto6- hydroxy compound is A-pregnene-6 8,2l-diol-3,20-dione.

4. The process of claim 1 wherein the A -3-ket0-6- hydroxy compound isthe 21-acetate of A -pregnene- 6fi,2l-diol-3,20-di one.

5. The process of claim 1 wherein the A -3-keto-6- hydroxy compound is A-androstene-6/3-o1-3,l?dione.

6. The process of claim 1 wherein the A -3-keto-6- hydroxy compound is A-androstene-6fl,l7fi-diol-3-one.

Murray .4... July 8, 1952 Murray July 13, 1954

1. A PROCESS FOR THE PRODUCTION OF A $4-3-KETO-6HYDROXY COMPOUNDSELECTED FROM THE GROUP CONSISTING OF COMPOUNDS OF THE PREGNEN SERIESAND COMPOUNDS OF THE ANDROSTENE SERIES WHICH COMPRISES TREATING ACORRESPONDING $4-3,6-DIHYDROXY COMPOUND WITH MANGANESE DIOXIDE AT ROOMTEMPERATURE.